As liquid crystal display devices have increasingly been applied to television sets and the screen size has been expanding in recent years, there have been increasing needs for higher quality of image and lower cost. In addition, as liquid crystal display devices have increasingly been installed and used outdoors, the liquid crystal display devices have been required to be more durable under harsh environments.
As for polarizing plate in the liquid crystal display device, it is widely known to hold a polarizer, made of polyvinyl alcohol (PVA) and iodine, between polarizing plate protective films to thereby improve the durability. Various resin films, including cellulose acylate film and acrylic resin film, have been used for the polarizing plate protective film, for which toughness and good optical characteristics have been required.
Patent Literature 1 describes a cellulose acylate film with suitably controlled retardation and adhesiveness with the polarizer, showing in-plane orientation in a zone, which ranges from at least one surface of the film to a depth of 0 to 3 μm, lower than in-plane orientation in a 3 to 10 μm-deep zone.
Patent Literature 2 describes a polarizer which contains a polyvinyl alcohol-based resin, a dichroic dye, and 0.01 to 10 parts by mass, relative to the polyvinyl alcohol-based resin, of an organic acid having a specific structure. The polarizer is reportedly improved in durability of the polarizer under high-temperature and high-humidity conditions, and high-temperature and low-humidity conditions.